The Securities and Exchange Commission has not necessarily reviewed the information in this filing and has not determined if it is accurate and complete.
The reader should not assume that the information is accurate and complete.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM 13F

FORM 13F INFORMATION TABLE
OMB APPROVAL
OMB Number: 3235-0006
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COLUMN 1 COLUMN 2 COLUMN 3 COLUMN 4 COLUMN 5 COLUMN 6 COLUMN 7 COLUMN 8
VALUE SHRS OR SH/ PUT/ INVESTMENT OTHER VOTING AUTHORITY
NAME OF ISSUER TITLE OF CLASS CUSIP (x$1000) PRN AMT PRN CALL DISCRETION MANAGER SOLE SHARED NONE
58.com Inc ADR COM 31680q104 198,891 3,015,330 SH   SOLE   3,015,330 0 0
AT&T Inc COM 00206r102 3,238 94,104 SH   SOLE   94,104 0 0
Affiliated Managers Group Inc COM 008252108 818 5,120 SH   SOLE   5,120 0 0
Align Technology Inc. COM 016255101 4,516 68,586 SH   SOLE   68,586 0 0
Allergan PLC COM g0177j108 339,334 1,085,870 SH   SOLE   1,085,870 0 0
Alphabet Inc Cl A COM 02079K305 404,320 519,685 SH   SOLE   519,685 0 0
Alphabet Inc. Cl C COM 02079K107 441,234 581,428 SH   SOLE   581,428 0 0
Altria Group Inc COM 02209S103 4,457 76,574 SH   SOLE   76,574 0 0
American Electric Power COM 025537101 902 15,485 SH   SOLE   15,485 0 0
American Express COM 025816109 94,658 1,361,001 SH   SOLE   1,361,001 0 0
Amgen COM 031162100 327 2,017 SH   SOLE   2,017 0 0
Apple Computer COM 037833100 1,507 14,316 SH   SOLE   14,316 0 0
Applied Materials COM 038222105 256 13,692 SH   SOLE   13,692 0 0
Arch Capital Group Ltd COM g0450a105 662 9,488 SH   SOLE   9,488 0 0
Athenahealth Inc. COM 04685w103 32,194 200,000 SH   SOLE   200,000 0 0
Autohome Inc ADR COM 05278c107 3,302 94,550 SH   SOLE   94,550 0 0
Automatic Data Processing COM 053015103 528 6,238 SH   SOLE   6,238 0 0
Bank of America Corp COM 060505104 346 20,580 SH   SOLE   20,580 0 0
Bed Bath & Beyond Inc COM 075896100 293 6,075 SH   SOLE   6,075 0 0
Berkshire Hathaway - Cl A COM 084670108 1,822,134 9,212 SH   SOLE   9,212 0 0
Berkshire Hathaway - Cl B COM 084670702 648,427 4,910,840 SH   SOLE   4,910,840 0 0
Bio-Techne Corp COM 09073m104 229 2,540 SH   SOLE   2,540 0 0
Boeing COM 097023105 259 1,790 SH   SOLE   1,790 0 0
Bristol-Myers Squibb COM 110122108 252 3,670 SH   SOLE   3,670 0 0
Brown & Brown Inc. COM 115236101 45,450 1,415,900 SH   SOLE   1,415,900 0 0
CVS Corp. COM 126650100 1,775 18,153 SH   SOLE   18,153 0 0
Cabelas Inc. Cl A COM 126804301 155,623 3,330,267 SH   SOLE   3,330,267 0 0
Cable One Inc. COM 12685J105 1,403 3,236 SH   SOLE   3,236 0 0
Canadian Natural Resources COM 136385101 15,913 728,973 SH   SOLE   728,973 0 0
Caterpillar COM 149123101 4,654 68,479 SH   SOLE   68,479 0 0
Chemours Co. COM 163851108 60 11,150 SH   SOLE   11,150 0 0
ChevronTexaco Corp COM 166764100 534 5,940 SH   SOLE   5,940 0 0
Chubb COM 171232101 295 2,222 SH   SOLE   2,222 0 0
Citigroup Inc COM 172967424 308 5,948 SH   SOLE   5,948 0 0
Coca Cola Co. COM 191216100 28,877 672,185 SH   SOLE   672,185 0 0
Colfax Corp COM 194014106 11,708 501,400 SH   SOLE   501,400 0 0
Colgate Palmolive Co. COM 194162103 247 3,715 SH   SOLE   3,715 0 0
Comcast Corp. Cl A COM 20030n101 495 8,777 SH   SOLE   8,777 0 0
ConocoPhillips COM 20825c104 3,698 79,200 SH   SOLE   79,200 0 0
Costco Wholesale Corp COM 22160k105 119,627 740,722 SH   SOLE   740,722 0 0
Cresud SACIFYA Spon ADR Repstg COM 226406106 7,897 612,147 SH   SOLE   612,147 0 0
Danaher Corp. COM 235851102 132,373 1,425,206 SH   SOLE   1,425,206 0 0
Disney Walt COM 254687106 2,893 27,531 SH   SOLE   27,531 0 0
Du Pont E I De Nemours & Co. COM 263534109 3,714 55,762 SH   SOLE   55,762 0 0
Edison International COM 281020107 2,540 42,900 SH   SOLE   42,900 0 0
Emcor Group Inc COM 29084q100 76,647 1,595,487 SH   SOLE   1,595,487 0 0
Emerson Electric COM 291011104 298 6,232 SH   SOLE   6,232 0 0
Expeditors Int'l of Wash. Inc. COM 302130109 3,127 69,332 SH   SOLE   69,332 0 0
Express Scripts Holding Co. COM 30219g108 383 4,379 SH   SOLE   4,379 0 0
Exxon Mobil Corp COM 30231g103 6,480 83,134 SH   SOLE   83,134 0 0
Fastenal Co COM 311900104 963,644 23,607,163 SH   SOLE   23,607,163 0 0
Fifth Third Bancorp COM 316773100 2,249 111,881 SH   SOLE   111,881 0 0
General Electric COM 369604103 7,165 230,023 SH   SOLE   230,023 0 0
Goldman Sachs Group Inc COM 38141g104 138,692 769,530 SH   SOLE   769,530 0 0
Graham Holdings Co. COM 384637104 1,569 3,236 SH   SOLE   3,236 0 0
Groupon Inc. COM 399473107 9,220 3,003,417 SH   SOLE   3,003,417 0 0
HDFC Bank Ltd ADR Repstg 3 Shs COM 40415f101 1,129 18,328 SH   SOLE   18,328 0 0
Heartland Express COM 422347104 1,720 101,057 SH   SOLE   101,057 0 0
Hexcel Corp COM 428291108 46,582 1,002,840 SH   SOLE   1,002,840 0 0
Home Depot COM 437076102 3,892 29,428 SH   SOLE   29,428 0 0
IAC Interactivecorp COM 44919p300 72,385 1,205,405 SH   SOLE   1,205,405 0 0
IBM COM 459200101 171,559 1,246,612 SH   SOLE   1,246,612 0 0
Idex Corp COM 45167R104 400 5,225 SH   SOLE   5,225 0 0
Idexx Laboratories Corp. COM 45168D104 585,356 8,027,368 SH   SOLE   8,027,368 0 0
Interactive Brokers Group Inc COM 45841n107 43,684 1,001,923 SH   SOLE   1,001,923 0 0
JP Morgan Chase & Co. COM 46625h100 1,476 22,350 SH   SOLE   22,350 0 0
Jacobs Engineering Group Inc COM 469814107 250,502 5,971,440 SH   SOLE   5,971,440 0 0
Johnson & Johnson COM 478160104 6,651 64,753 SH   SOLE   64,753 0 0
Kraft Heinz Co. COM 500754106 1,264 17,378 SH   SOLE   17,378 0 0
LKQ Corp. COM 501889208 4,800 162,000 SH   SOLE   162,000 0 0
Lennox International Inc. COM 526107107 1,565 12,527 SH   SOLE   12,527 0 0
Leucadia Nat'l COM 527288104 286 16,471 SH   SOLE   16,471 0 0
Liberty Lilac Group CL C COM g5480u153 3,661 85,150 SH   SOLE   85,150 0 0
Linear Technology Group COM 535678106 5,098 120,046 SH   SOLE   120,046 0 0
Lockheed Martin Corp. COM 539830109 550 2,535 SH   SOLE   2,535 0 0
Lowe's Companies Inc. COM 548661107 784 10,311 SH   SOLE   10,311 0 0
Makemytrip Ltd COM v5633w109 48,285 2,813,802 SH   SOLE   2,813,802 0 0
Mastercard Inc COM 57636q104 517,872 5,319,142 SH   SOLE   5,319,142 0 0
Match Group Inc. COM 57665r106 9,485 700,000 SH   SOLE   700,000 0 0
McDonalds COM 580135101 14,649 123,999 SH   SOLE   123,999 0 0
McGraw Hill COM 580645109 379 3,840 SH   SOLE   3,840 0 0
Medtronic PLC COM G5960l103 390 5,075 SH   SOLE   5,075 0 0
Merck & Co. COM 58933y105 264 4,994 SH   SOLE   4,994 0 0
Microsoft COM 594918104 3,361 60,579 SH   SOLE   60,579 0 0
Mohawk Industries COM 608190104 515,662 2,722,754 SH   SOLE   2,722,754 0 0
Mondelez International COM 50075n104 2,535 56,542 SH   SOLE   56,542 0 0
Monsanto Co COM 61166w101 94,225 956,402 SH   SOLE   956,402 0 0
Novo Nordisk A/S ADR COM 670100205 4,723 81,320 SH   SOLE   81,320 0 0
O Reilly Automotive Inc COM 67103h107 896,294 3,536,791 SH   SOLE   3,536,791 0 0
Omnicom Group COM 681919106 210,946 2,788,079 SH   SOLE   2,788,079 0 0
PepsiCo COM 713448108 16,016 160,292 SH   SOLE   160,292 0 0
Perrigo Co PLC COM G97822103 209,402 1,447,149 SH   SOLE   1,447,149 0 0
Pfizer COM 717081103 479 14,850 SH   SOLE   14,850 0 0
Philip Morris Intl Inc. COM 718172109 7,999 90,990 SH   SOLE   90,990 0 0
Phillips 66 COM 718546104 3,242 39,637 SH   SOLE   39,637 0 0
Pioneer Natural Resources Co. COM 723787107 496 3,952 SH   SOLE   3,952 0 0
Praxair COM 74005P104 183,675 1,793,700 SH   SOLE   1,793,700 0 0
Precision Castparts Corp COM 740189105 1,098,036 4,732,708 SH   SOLE   4,732,708 0 0
Price T Rowe Group Inc COM 74144t108 289 4,045 SH   SOLE   4,045 0 0
Primerica Inc COM 74164M108 136,143 2,882,551 SH   SOLE   2,882,551 0 0
Procter & Gamble COM 742718109 10,114 127,366 SH   SOLE   127,366 0 0
Progressive Corp. Ohio COM 743315103 1,584 49,798 SH   SOLE   49,798 0 0
Public Storage Inc. COM 74460d109 618 2,493 SH   SOLE   2,493 0 0
Range Resources Corp COM 75281a109 145,439 5,909,755 SH   SOLE   5,909,755 0 0
Republic Services Inc Cl A COM 760759100 537 12,198 SH   SOLE   12,198 0 0
Resource America Inc - (RESTRI COM 761195205 1,803 294,117 SH   SOLE   294,117 0 0
Resource America Inc Cl A COM 761195205 3,697 603,180 SH   SOLE   603,180 0 0
Robert Half Internat'l COM 770323103 330 7,000 SH   SOLE   7,000 0 0
Roper Industries Inc New COM 776696106 847 4,465 SH   SOLE   4,465 0 0
Royal Bk CDA Montreal Que COM 780087102 2,700 50,400 SH   SOLE   50,400 0 0
Royal Dutch Shell PLC Spon ADR COM 780259206 975 21,299 SH   SOLE   21,299 0 0
Ryanair Holdings PLC ADR COM 783513104 469 5,424 SH   SOLE   5,424 0 0
Schlumberger Ltd COM 806857108 2,684 38,486 SH   SOLE   38,486 0 0
Sherwin Williams Co. COM 824348106 1,378 5,307 SH   SOLE   5,307 0 0
Sirona Dental Systems Inc COM 82966c103 305,656 2,789,596 SH   SOLE   2,789,596 0 0
Soufun Holdings LTD ADR COM 836034108 7,453 1,008,500 SH   SOLE   1,008,500 0 0
Stericycle Inc. COM 858912108 362 3,000 SH   SOLE   3,000 0 0
Suntrust Banks COM 867914103 1,337 31,203 SH   SOLE   31,203 0 0
Symetra Finl Corp COM 87151q106 397 12,500 SH   SOLE   12,500 0 0
TJX Cos - New COM 872540109 1,237,938 17,457,872 SH   SOLE   17,457,872 0 0
Thermo Electron COM 883556102 408 2,873 SH   SOLE   2,873 0 0
Third Point Reinsurance LTD COM g8827u100 40,630 3,029,800 SH   SOLE   3,029,800 0 0
Tiffany & Co COM 886547108 163,773 2,146,719 SH   SOLE   2,146,719 0 0
Time Warner Cable Inc. COM 88732j207 9,673 52,118 SH   SOLE   52,118 0 0
Time Warner Inc COM 887317303 11,610 179,523 SH   SOLE   179,523 0 0
Trimble Navigation Ltd. COM 896239100 69,754 3,251,927 SH   SOLE   3,251,927 0 0
U.S. Bancorp New - Del. COM 902973304 952 22,319 SH   SOLE   22,319 0 0
Union Pacific COM 907818108 7,886 100,846 SH   SOLE   100,846 0 0
Valeant Pharmaceuticals Intern COM 91911k102 3,595,931 35,375,610 SH   SOLE   35,375,610 0 0
Verisk Analytics Class A COM 92345Y106 4,475 58,211 SH   SOLE   58,211 0 0
Verizon Communications COM 92343v104 266 5,756 SH   SOLE   5,756 0 0
Vipshop Hldgs Ltd ADR COM 92763w103 16,873 1,105,000 SH   SOLE   1,105,000 0 0
Visa Inc Class A COM 92826C839 257,042 3,314,535 SH   SOLE   3,314,535 0 0
WPP PLC New ADR COM 92937a102 326 2,840 SH   SOLE   2,840 0 0
Wal-Mart Stores COM 931142103 128,763 2,100,532 SH   SOLE   2,100,532 0 0
Waters Corp COM 941848103 268,520 1,995,247 SH   SOLE   1,995,247 0 0
Wells Fargo & Co. New COM 949746101 7,866 144,700 SH   SOLE   144,700 0 0
West Pharmaceutical Svcs Inc C COM 955306105 59,734 991,928 SH   SOLE   991,928 0 0
Yandex NV Shs COM n97284108 56,647 3,603,523 SH   SOLE   3,603,523 0 0
Yelp Inc. COM 985817105 3,102 107,700 SH   SOLE   107,700 0 0
Young Broadcasting Inc Cl A COM 987434107 0 144,865 SH   SOLE   144,865 0 0
Zoetis Inc. COM 98978v103 7,262 151,537 SH   SOLE   151,537 0 0
Constellation Software Inc. COM 21037x100 181,073 435,954 SH   SOLE   435,954 0 0
Senvest Capital Inc. COM 81731l109 3,893 35,000 SH   SOLE   35,000 0 0